This study proposes an update, expansion and methodological refinement of the applicant's original meta-analysis of 143 adolescent drug prevention programs for the purpose of comparing the relative impact of a program's strategy in reducing teenage drug use. It identified two strategies that were successful in impacting drug use, one for school-based youth and one for the "at risk" youth. Meta-analysis techniques will be adapted to provide a systematic approach for the accumulation, quantification, integration and statistical analysis of the numerous research findings. The proposal builds on the applicant's comprehensive set of experimental and quasi-experimental studies. The expanded data base would provide information on relative effectiveness of various strategies - at what age, and for which drugs, for both the general and "at risk" youth populations. Examination of implementation factors such as presenter training, optimum delivery intensity could supply data on cost effectiveness. A review conducted in this manner would result in the information sought by policy makers for their decision making process.